[SOLVED] Reply to message loses focus in web client

When using the AJAX web client on any OS/Browser combination focus is lost when initiating a reply to a message.

When replying to a message the focus starts in the message pane and then is lost in the process of loading the child page. So that when loading is complete the focus is undetermined. Pressing the Tab key cycles the focus to the Send or in the reverse (Shift + Tab) ends up at the Subject line.

I am having the same problem on multiple OSes and multiple browsers ever since we upgraded to 6.0.10. My users are complaining constantly about the changed behavior. I looked for the Zimlet mentioned, but we do not even have one by that name in our installation. Any other ideas?